MXPA04011922A

MXPA04011922A - Anisotropic polymer foam.

Info

Publication number: MXPA04011922A
Application number: MXPA04011922A
Authority: MX
Inventors: Z Weekley Mitchell
Original assignee: Owens Corning Fiberglass Corp
Priority date: 2002-05-31
Filing date: 2003-05-12
Publication date: 2005-03-31
Also published as: ATE538164T1; CN1880369A; CN1656158A; EP1511795B1; EP1511795A2; TW200400223A; US20160068648A1; EP2348066A2; CN100467523C; WO2003102064A3; AU2003233528A1; US20030225172A1; TWI318224B; CA2486159A1; CA2486159C; WO2003102064A2; JP2005528494A; EP2348066A3; US20050192368A1; CN1315922C

Abstract

This invention relates to foam insulating products, particularly extruded polystyrene foam, with cell orientation ratio in the X/Z direction of approximatively 0,5 to 0,97 and low cell anisotropic ratio.

Description

IMPROVING THE THERMAL INSULATION OF POLYMERIC SPXJMA, BY REDUCING THE ANISOTROPIC CELLULAR PROPORTION AND THE METHOD FOR THEIR PRODUCTION TECHNICAL FIELD AND INDUSTRIAL APPLICABILITY OF THE INVENTION The present invention relates to improving the thermal insulation value (or decreasing the thermal conductivity) of polymeric boards. of rigid foam, by reducing the cellular anisotropic ratio and by increasing the proportion of cellular orientation, as well as the process methods for its production. More particularly, it refers to rigid extruded polystyrene foam board wherein low cellular anisotropic ratio or high proportion of cellular orientation is achieved to increase the thermal insulation value of the rigid foamed board. BACKGROUND OF THE INVENTION The utility of rigid foamed polymeric boards in a variety of applications is well known. Rigid foamed plastic boards are widely used as thermal insulation materials for many applications. For example, polymer foam boards are widely used as insulating members in the construction industry. In the past, infrared attenuating agents have been used as fillers or fillers in polymer foam boards to minimize the thermal conductivity of material k which in turn maximizes the insulation capacity to (increase the R value) for a given thickness (U.S. Patent Nos. 5,373,026 and 5,604,265; EP 863,175). The thermal transfer k through an insulating material can occur through conductivity of solids, conductivity of gases, radiation and convection. The thermal transfer k or factor K is defined as the ratio of thermal flux per unit cross section to the temperature drop per unit thickness. In units of the U.S. , this is defined as: Btu. in hr. ft2. ° F And the metric unit: W k In most polymeric foams of conventional cell size, this is 0.1 to 1.5 millimeters, the reduction in thermal conductivity has been observed by decreasing the average cell size. This phenomenon is documented in "The Thermal Conductivity of Foamed Plastics" Chemical Engineering Progress, Vol. 57, No. 10, p. 55-59, by author Richard E. Skochdopol of The Dow Chemical Co., and "Prediction of the Radiation Term in the Thermal Conductivity of Crosslinked Closed Cell Polyolefin Foams" (Prediction of Radiation Term in the Thermal Conductivity of Polyolefin Foams Closed Interlaced Cells) J. of Polymer Science: Part B: Polymer Physics, V 38, pp. 993-1004 (2000), by O.A. Almanza and collaborators, of the University of Valladolid, that here are incorporated by reference. It is highly desirable to improve the thermal conductivity k without adding additives or increasing the density and / or thickness of the foam product. Particularly, the architectural community desires a foam board that has a thermal resistance value R equal to 10, with a thickness less than 44.45 millimeters (1.75 inches) for cavity wall construction, to keep at least 25.4 millimeters (1 inch) free ) of the air space of the cavity. The total thermal resistance R, also known as the value R, is the ratio of the thickness t of the board to the thermal conductivity Je.

It is also highly desirable to produce the above rigid polymer foam having retained or improved properties of compression strength, thermal dimensional stability, fire resistance and water absorption. It is also highly desirable to provide the above rigid polymer foam with infrared attenuation agents and other process additives such as nucleating agents, flame retardants, gas barriers, which have total compounding effects on the foam properties including improved thermal conductivity (factor k). decreased), and improved insulating value (increased R value) for certain thickness and density. It is also highly desirable to provide the above rigid polymer foam with a variety of blowing agents to improve the R value of thermal insulation. These blowing agents include partially or fully hydrogenated chlorofluorocarbons (HCFC's), hydrofluorocarbons (HFC's), hydrocarbons (HC's), water, carbon dioxide and other inert gases. It is also highly convenient to provide the process methods and modify the foaming facility to control the cell morphology: reduce cellular anisotropy and increase the orientation of the cells during the foaming process, to be used in the production of a rigid polymer foam . It is also highly convenient to reduce the cost of a polymeric foam product in a simple and economical way. SUMMARY OF THE INVENTION The present invention, in a preferred embodiment, relates to foam insulating products, such as extruded polystyrene foam, with low cellular anisotropic ratio or superior cellular orientation in the x / z direction, to improve thermal insulation and retain other properties equally. The greater the cell orientation can be achieved easily through process and matrix / conformer modification. The polystyrene foams of low anisotropic proportion or higher cellular orientation of the present invention, decrease both the initial and aged thermal conductivity or on the contrary, increase the thermal resistance ("R value") in comparison with substantially round cells. In another preferred embodiment of the present invention, polymeric foams with a lower cell orientation ratio in the x / z direction and higher anisotropic ratio can be easily achieved through process modification and / or matrix / former. Cells made in this way have improved compression properties with only slight reductions in thermal conductivity and R insulation values compared to round cells. The foregoing and other advantages of the invention will be apparent from the following description in which one or more preferred embodiments of the invention are described in detail and illustrated in the accompanying drawings. It will be contemplated that variations in procedures, structural characteristics and arrangements of parts can occur to a person with skill in the specialty, without departing from the scope or sacrifice any of the advantages of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 illustrates a rigid, low density foam made according to the prior art; Figure 2 illustrates a rigid low density foam made according to a preferred embodiment of the present invention; Figure 3 illustrates a rigid low density foam made according to another preferred embodiment of the present invention; Figure 4 is a graphic illustration of 52 tests showing the R value of thermal insulation versus cell orientation ratio (x / z) of the rigid foam board with various density levels over a period of 180 days, HCFC 142 b agent blown, 10.5 to 11.5 weight percent of total solids was used; Figure 5 is a graph showing test results of 39 tests, related to R value against cellular guidance of polystyrene foam boards with various density levels, over a period of 180 days, BFC134a 5.5% by weight and 3% ethanol by weight they were used as blowing agents to foam these boards; and Figure 6 is a graph, showing test results of 32 tests, related to R value against cellular orientation ratio of polystyrene foam boards, with various density levels, over a period of 40 days at the diffusion equilibrium of gas, carbon dioxide 3.68% by weight and ethanol 1.4% by weight, were used as a blowing agent.

DETAILED DESCRIPTION AND PREFERRED MODALITIES OF THE INVENTION The present invention relates to foam insulating products, such as extruded or expanded polystyrene foam, which are widely used as thermal insulating materials for many applications. For example, polymer foam boards are widely used as insulating members in building construction. Figure 1 illustrates a cross-sectional view of rigid foam materials 20 made according to the prior art, while Figure 2 illustrates foam cells having improved thermal insulation values made according to a preferred embodiment of the invention. present invention. Figure 3 illustrates another rigid foam material 20 made according to a preferred embodiment of the present invention having improved compressive strength. With reference to Figure 1, a rigid foam plastic material 20, typically a foam board, made according to the prior art, is illustrated to have a plurality of inner open cells 22 and outer open cells 24. Each inner open cell 22 is separated from the next corresponding inner open cell 22 and / or outer open cell 24 by a column or cell support 26, which is each open cell 22 shares a cell column 26 with the next respective open cell 22. Similarly, each outer open cell 24 is separated from the next corresponding open outer cell 24 by a cell column 26. Further, each outer open cell 24 is separated from the outer environment surrounding the rigid foam plastic materials 20, by a cellular wall 28. The thickness of the cell wall 28 is smaller than the thickness of a cell column 26. The cells 22, 24 are substantially round in shape and have a size of average cells of approximately 0.1 to 1.5 millimeters in diameter. Since cells 22, 24 are substantially round, the cell orientation ratio x / z is approximately 1.0. The cell orientation ratio is simply a ratio of the cell size in the desired direction. For example, the orientation of cells in the machine direction (or extruded direction) is defined as the cell orientation ratio x / z and in the machine cross direction as the cell orientation ratio and / z. In addition, the cellular anisotropic ratio of substantially round cells as in Figure 1 is also about 1.0. Here, the cellular anisotropic ratio a is determined as: a = z / (xyz) 1/3 o, for easy calculation: a = 10? 3? "1/3 (ag x'y-z) where x is the cell size 22, 24 of the foamed plastic material 20 in the extruded direction and is the cell size 22, 24 in the cross machine direction of the material 20; and z is the cell size 22, 24 in the vertical thickness direction of the material 20. The cell sizes are measured by optical microscope or scanning electron microscope (SEM = Scanning Electron Microscope); that at least two sliced faces are observed - in the x / z plane and the y / z plane, and are characterized by image analysis program. The average cell size 22, 24, c is calculated by: c = (x + y + z) / 3 Figures 2 and 3 illustrate a rigid foam plastic material 20 made in accordance with the present invention wherein the proportion of Cell orientation in the x / z direction is altered from 1.0. As will be shown, the change in cell orientation ratio in the x / z direction results in new and unique properties for rigid foam plastic materials 20.

Figure 2 shows a rigid foam plastic material 20 having rigid foam cells 22, 24, made according to a preferred embodiment of the present invention. Here, the proportion of cell orientation in the x / z direction increases over 1.0 to between about 1.03 and 2.0, while still maintaining a low cellular anisotropic ratio between 0.97 and 0.6. Materials 20 made in accordance with Figure 2 exhibit an R value of improved thermal insulation, decreased thermal conductivity k, and decreased aged thermal conductivity without an increase in the amount of polymeric material per unit measure and without a substantial decrease in compression strength. In Figure 3, the cell orientation in the x / z direction decreases between approximately 0.5 and 0.97 while maintaining an anisotropic ratio of between 1.6 and 1.03. Materials 20 made in accordance with Figure 3 exhibit an R value of decreased thermal insulation, increased thermal conductivity k, and increased aged thermal conductivity without an increase in the amount of polymeric material per unit measure. However, these materials 20 reach an increase in compressive strength.

The composition of the columns of the cells 26 and the cell walls 28 of Figures 2 and 3 can be any of these polymer materials suitable for producing the polymer foams. These include polyolefins, polyvinyl chloride, polycarbonates, polyetherimides, polyamides, polyesters, polyvinylidene chloride, polymethyl ethacrylate, polyurethanes, polyurea, phenol formaldehyde, polyisocyanurates, phenolics, copolymers and terpolymers of the foregoing, mixtures of thermoplastic polymers, rubber modified polymers and the like . Suitable polyolefins comprising polyethylene and polypropylene, and ethylene copolymers are also included. Preferably, these thermoplastic polymers have weight average molecular weights of from about 30,000 to about 500,000. A preferred thermoplastic polymer comprises an alkenyl aromatic polymer material. Suitable alkenyl aromatic polymer materials include alkenyl aromatic homopolymers and copolymers of alkenyl aromatic compounds and copolymerizable ethylenically unsaturated comonomers. The alkenyl aromatic polymer material may also include minor proportions of non-alkenyl aromatic polymers. The alkenyl aromatic polymer material may be formed in a single form of one or more alkenyl aromatic homopolymers, one or more alkenyl aromatic copolymers, a mixture of one or more of each of alkenyl aromatic homopolymers and copolymers or mixtures of any of the foregoing with a non-alkenyl aromatic polymer. Suitable alkenyl aromatic polymers include those derived from alkenyl aromatic compounds such as styrene, alphamethylstyrene, paramethylstyrene, ethylstyrene, vinylbenzene, vinyl toluene, chlorostyrene and bromostyrene. A preferred alkenyl aromatic polymer is polystyrene. Minor amounts of monoethylenically unsaturated compounds such as C2-6 alkyl acids and esters, ionomeric derivatives, and C4_6 dienes can be copolymerized with alkenyl aromatic compounds. Examples of copolymerizable compounds include acrylic acid, methacrylic acid, ethacrylic acid, maleic acid, itaconic acid, acrylonitrile, maleic anhydride, methyl acrylate, ethyl acrylate, isobutylacrylate, n-butyl acrylate, methyl methacrylate, vinyl acetate and butadiene. Any convenient blowing agent can be employed in the practice of this invention. Blowing agents useful in the practice of this invention include inorganic agents, organic blowing agents and chemical blowing agents. Suitable inorganic blowing agents include carbon dioxide, nitrogen, argon, water, air, nitrogen and helium. Organic blowing agents include aliphatic hydrocarbons having 1-9 carbon atoms, aliphatic alcohols having 1-3 carbon atoms and total and partially halogenated aliphatic hydrocarbons having 1-4 carbon atoms. Aliphatic hydrocarbons include methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane and neopentane. Aliphatic alcohols include methanol, ethanol, n-propanol and isopropanol. Total and partially halogenated aliphatic hydrocarbons include fluorocarbons, chlorocarbons and chlorofluorocarbons. Examples of fluorocarbons include methyl fluoride, perfluoromethane, ethyl fluoride, 1,1-difluoroethane (HFC-152a), 1,1-trifluoroethane (HFC-143a), 1,1,1,2-tetrafluoroethane (HFC) -134a), pentafluoroethane, difluoromethane, perfluoroethane, 2, 2-difluoropropane, 1,1, 1-trifluoropropane, perfluoropropane, dichloropropane, difluoropropane, perfluorobutane and perfluorocyclobutane. Chlorocarbons and partially halogenated chlorofluorocarbons for use in this invention include methyl chloride, methylene chloride, ethyl chloride, 1,1,1-trichloroethane, 1,1-dichloro-1-fluoroethane (HCFC-141b), 1-chloro- 1,1-difluoroethane (HCFC-142b), chlorodifluoromethane (HCFC-22), 1,1-dichloro-2,2,2-trifluoroethane (HCFC-123) and 1-chloro-1,2,2,2-tetrafluoroethane (HCFC-124), and the like.

Fully halogenated chlorofluorocarbons include trichloromonofluoromethane (CFC-11), dichlorodifluoromethane (CFC-12), trichlorotrifluoroethane (CFC-113), 1,1-trifluoroethane, pentafluoroethane, dichlorotetrafluoroethane (CFC-114), chlorheptafluoropropane and dichlorohexafluoropropane. Chemical blowing agents include azodicarbonamide, azodiisobutyro-nitrile, benzensulfonhydrazide, 4,4-oxybenzene sulphonyl-semicarbazide, p-toluene sulfonyl semi-carbazide, barium azodicarboxylate, and?,? '- dimethyl-?,? -dinitrosotereftalamide and trihydrazino triazine. In the present invention, it is preferable to use 8 to 14% by weight, based on the weight of the HCFC-142b polymer or 4 to 12% of BFC-134a with 0 to 3% ethanol. Alternately, 3 to 8% carbon dioxide with 0 to 4% lower alcohol, which include ethanol, methanol, propanol, isopropanol and butanol.

Optional additives that can be incorporated in the extruded foam product include additional infrared attenuating agents, plasticizers, flame retardant chemicals, pigments, elastomers, extrusion aids, antioxidants, fillers or fillers, antistatic agents, UV absorbers, etc. These optional additives can be included in any quantity to obtain the desired characteristics of the foamable gel or extruded foam products. Preferably, optional additives are added to the resin mixture but can be added in alternate forms to the extruded foam manufacturing process. Thus, for example, in the preferred embodiments having a structure as illustrated in Figures 2 and 3 above, the rigid foam plastic material 20 is formed of a polystyrene plasticized resin mixture having an average molecular weight in weight of about 250,000, an infrared attenuation agent such as special asphalt, a blowing agent and other process additives such as a nucleating agent, flame retardant chemicals, and a nano-gas barrier additive.

The rigid foam plastic material 20 of Figures 2 and 3 can be prepared by any means known in the art such as by an extruder, mixer, blender or the like. The plasticized resin mixture containing the thermoplastic polymer and preferably other additives is heated to the melt mixing temperature and mixed thoroughly. The melting mixing temperature may be sufficient to plasticize or melt the thermoplastic polymer. Therefore, the melting mixing temperature is at or above the glass transition temperature or melting point of the polymer. The melt mixing temperature is 200 ° C (392 ° F) to 280 ° C (536 ° F), more preferably from about 220 ° C (428 ° F) to 240 ° C (464 ° F), depending on the the amount of additives and the type of blowing agent used. A blowing agent is then incorporated to form a foamable gel. The foamable gel is then cooled to a matrix melting temperature. The matrix melt temperature is typically cooler than the melt mix temperature, in the preferred embodiment, from 100 ° C (212 ° F) to about 150 ° C (302 ° F), and more preferably about 110 ° C (230 ° F) at approximately 120 ° C (248 ° F). The matrix pressure should be sufficient to prevent pre-foaming of the foamable gel containing the blowing agent. Pre-foaming involves the undesirable premature foaming of the foamable gel before extrusion in a region of reduced pressure. Accordingly, the matrix pressure varies depending on the identity and amount of the blowing agent in the foamable gel. Preferably, in the preferred embodiment as illustrated in Figures 2 and 3, the pressure is from 40 to 70 bars, more preferably around 50 bars. The rate of expansion, foam thickness per matrix space is in the range of 20 to 70, typical of about 60. To produce materials 20 of Figure 2 that have a ratio of cell orientation in the x / z direction between 1.03 and 2, the space of the matrix lips and / or the matrix forming plates opens wider compared to those produced in the prior art as illustrated in Figure 1. This produces materials 20 having a thickness greater than desired . The line speed or conveyor extraction speed is then used to extract the materials 20 to the desired thickness. As described above, materials 20 made according to Figure 2 exhibit an R value of improved thermal insulation, decreased thermal conductivity k, and decreased aged thermal conductivity, without an increase in the amount of polymeric material per unit measure and without a decrease substantial in compressive strength compared to substantially round cell materials 20 as in Figure 1. Conversely, for materials 20 having a cell orientation ratio in the x / z direction between 0.97 and 0.6, the lip space The matrix and / or matrix forming plates are closed and the conveyor line speed is decreased compared to the prior art as illustrated in Figure 1 to cause the cells 22, 24 to grow in the z direction. As described above, materials made according to Figure 3 have improved compressive strength without a substantial decrease in R value of thermal insulation, compared to substantially round cell materials 20 as in Figure 1. Of course, as those will recognize With skill in the specialty, other factors employed can influence the proportion of cell orientation in the x / z direction. For example, it is more difficult to influence smaller cells 22, 24 than to affect larger cells 22, 24. In this way blowing agents that produce sizes of smaller cells such as carbon dioxide, may be more difficult to influence than blowing agents that produce larger cell sizes such as HCFC-142b. In another preferred embodiment, an extruded polystyrene polymer foam similar to the foam material 20 of Figures 2 and 3 is prepared by twin screw extruders (low shear) with flat matrix and plate former. A polystyrene strip or granule is added to the extruder together with a nucleating agent, a flame retardant and / or process agent by multiple feeders. Alternatively, a single-screw tandem extruder (high shear) with a radial die and a radial former can be used. The following are examples of the present invention suitable to the preferred embodiment as illustrated in Figure 2, and are not to be considered as limiting. EXAMPLES The invention is further illustrated by the following examples wherein all foam boards had a thickness of 38.1 millimeters (1.5 inches) and all R values were R-values aged 180 days, unless otherwise indicated. In the following examples and control examples, rigid polystyrene foam boards were prepared by a co-rotary twin screw extruder with a flat die and forming plate. Vacuum was applied in extrusion processes for some examples. Table 1 shows a summary of the process conditions for the twin screw extruder. The polystyrene resins used were 70% polystyrene with a melt index of 3 and 30% polystyrene having a melt index of 18.8 (both from Deltech, with molecular weight, Mw approximately 250,000). The composite melt index was about 27.43 cm (10.8 in) in the compound. Stabilized hexabromocyclododecane (Great Lakes Chemical, HBCD SP-75) was used as a retarding agent in the amount of 1% by weight of the solid foam polymer. TABLE 1 OPERATING PARAMETER KEY EXAMPLES% by weight of additive from 0 to 6 process OPERATING PARAMETER KEY EXAMPLES% by weight of talc 0-2% by weight of HC 0 to 3% by weight of BFC 134a 0 to 6% by weight of HCFC-142b 0-12% by weight of C02 0-5 Extruder Pressure, pa 13000- 17000 (psi) (1950 - 2400) Fusing Temperature of 117-123 Matrix, ° C Matrix Pressure, Kpa 5400 -6600 (psi) (790-950) Line Speed, m / hr 110-170 (6-9.5) (ft / min) Yield, kg / hr 100-200 Matrix Space, mm 0.4-1.8 KPa (inch) Vacuum Hg 0-4.25 (0 a twenty) Results of the previous examples and a comparative example of the conventional process with a round cell structure are shown in the Table TABLE 2 CORRIDA VALUE R DENSITY PROPORTION DO NOT. AGED 180 KG / M3 (PCF) ANISOTROPIC DAYS K.M2 / W OF CELL (F.FT2. HR / BTU) to 428-2 1,023 32.48 0.856 (5.81) (2.03) 431-3 0.997 32 0.911 (5.66) (2) 443-2 0.97 27.52 0.888 (5.51) ) (1.72) 445-2 0.912 27.36 0.989 (5.18) (1.71) 448-5 0.965 24.32 0.901 (5.48) (1.52) 459-2 0.912 23.36 0.977 (5.13) (1.46) 509-8 0.895 28.8 0.888 (5.08) ( 1.8) 498-2 0.852 28.18 0.982 (4.83) (1.76) 191-2 0.743 50.56 1.095 (4.22) (3.16) 183-4 0.696 49.76 1.215 CORRIDA VALUE R DENSITY PROPORTION NO. AGED 180 KG / 3 (PCF) ANISOTROPIC DAYS K.M2 / W OF CELL (F.FT2. HR / BTU) to (3.95) (3.11) TABLE 2 (CONT.) CORRIDA CELDA ORIENTACION CM (IN) OF AGENT OF NO. AVERAGE CELL X / Z HG OF VACUUM BLOWING) MICRAS 428-2 272 1.36 6 1 431-3 257 1.22 6.6 1 443-2 273 1.3 12 1 445-2 250 1.08 13.5 1 448-5 260 1.26 16.4 1 459-2 256 1.02 14 1 509-8 252 1.21 12.6 2 498-2 177 1.06 13 2 191-2 279 0.39 No 3 183-4 224 0.6 No 3 Note: All specimens have a thickness of 38 to 42 mm (about 1.5 inches) a where, aged R value is 40 days for carbon dioxide samples, -b Blowing agent compositions 1: HCFC 142 b 11% by weight; 2: BFC 134a 5.5% by weight and ethanol 3% by weight; 3: carbon dioxide 3.68% by weight and ethanol 1.4% by weight More complete data treatments of these tests are illustrated in Figure 4 as an illustration of 52 tests presenting the R value of thermal insulation against cell orientation rigid foam with various density levels, during a period of 180 days, blowing agent HCFC 142 b, 10.5 to 11.5 weight percent of total solids was used, which shows an increase in R value of 6 to 12% at change the cellular orientation from 0.9 to 1.3 for a foam board with a density of 25.63 kg / m3 (1.6 pcf). Figure 5 is a graph, showing test results of 39 tests, related to R value against cellular orientation of polystyrene foam boards with various density levels, over a period of 180 days, BFC 1 34 to 5.5% by weight and 3% ethanol by weight were used as a blowing agent for foaming these boards, which shows an increase in R value of 5 to 10% when changing the cellular orientation from 0.0 to 1.3 for a foam board with a density of 25,631 g / m3 (1.6 pcf). Figure 6 is a graph showing test results of 32 tests, related to the value R against, the cell-orientation of boards? of polystyrene foam with various density levels, over a period of 40 days at a gas diffusion equilibrium, carbon dioxide at 3.68% by weight and ethanol 1.4% by weight were used as a blowing agent, showing an increase in R value of 4 to 8%, when changing the cellular orientation from 0.7 to 0.9 for a foam board with a density of 48.06 kg / m3 (3 pcf). Based on the test data of all these tests from a multi-variable regression calculation, we obtain the R value against cell orientation (or Cell Anisotropic Ratio) as illustrated in Figures 4, 5 and 6, and that shows an increase of R value from 3 to 12% when increasing the cellular orientation 0.1 to 0.3 compared to projected R values of the same cellular structure, without change in cellular morphology of polymeric foams with different foam densities.

While the invention has been described in terms of preferred embodiments, it will be understood, of course, that the invention is not limited thereto, since modifications can be made by those skilled in the art, particularly in light of the foregoing teachings.

Claims

28 CLAIMS 1. A polymeric foam material, characterized in that it comprises: a polymer having a weight average molecular weight of between about 30,000 and 500,000; and a blowing agent; wherein the ratio of cellular orientation of polymeric foam material in the x / z direction is from about 0.5 to 0.97 and the anisotropic ratio range of 1.6 and 1.03. 2. The polymeric foam material according to claim 1, characterized in that it further comprises one or more additives selected from the group consisting of infrared attenuating agents, plasticizers, flame retardant chemicals, pigments, elastomers, extrusion aids, fillers or fillers. antioxidants, antistatic agents and UV absorbers. 3. The polymeric foam material according to claim 1, characterized in that the polymer is a thermoplastic polymer. 4. The polymeric foam material according to claim 3, characterized in that the polymer is an alkenyl aromatic polymer. 29 5. The polymeric foam material according to claim 4, characterized in that the alkenyl aromatic polymer is polystyrene. 6. The polymeric foam material according to claim 1, characterized in that the blowing agents comprise HCFC's, BFC's, HC's, carbon dioxide and other inert gases. 7. A polymeric foam material characterized in that it comprises: a polymer having a weight average molecular weight of between about 30,000 and 500,000; and a blowing agent; wherein the ratio of cellular orientation of the polymeric foam material in the x / z direction is from about 1.03 to 2.0 and the ratio range or anisotropic ratio is 0.97 and 0.6. 8. The polymeric foam material according to claim 7, characterized in that it further comprises one or more additives selected from the group consisting of infrared attenuation agents, plasticizers, flame retardant chemical compounds, pigments, elastomers, extrusion aids, fillers or Antioxidant charges, antistatic agents and UV absorbers. 30 9. The polymeric foam material according to claim 8, characterized in that the polymer is a thermoplastic polymer. 10. The polymeric foam material according to claim 9, characterized in that the polymer is an alkenyl aromatic polymer. 11. The polymeric foam material according to claim 10, characterized in that the alkenyl aromatic polymer is polystyrene. 12. The polymeric foam material according to claim 7, characterized in that the blowing agents comprise HCFC's, BFC's, HC's, carbon dioxide and other inert gases. 13. A method for improving R values of thermal insulation of rigid polymer foams used in insulation products, which comprises increasing the ratio of cellular orientation in the x / z direction of rigid polymeric foam materials between about 1.03 and 2.0. 14. Method according to claim 13, characterized in that increasing the proportion of cell orientation in the x / z direction of the rigid polymer foams comprises: providing a device capable of producing the rigid polymer foam material; enter a 31 thermoplastic polymer resin to the device; heating the thermoplastic polymer resin over its vitreous transition temperature and melting point; incorporating one or more blowing agents into the thermoplastic polymer resin at a first temperature to form a gel, the first pressure being sufficient to prevent pre-foaming of the gel; cooling the gel to a matrix melting temperature; and extrude the gel through a matrix space of the device, to a region of lower matrix pressure such that the gel grows faster in a direction x relative to a z-direction, to form the polymer foam material, wherein the direction x is defined as the extruder direction of the polymer foam material and wherein the z direction is defined as the vertical thickness direction of the polymer foam material. 15. Process according to claim 14, characterized in that the device comprises an extruder, a mixer or a blender. 16. Process according to claim 14, characterized in that the gel grows faster in the x direction with respect to the z direction, by increasing the line expression speed of the device through the matrix space at a matrix space thickness constant while it remains 32 a constant film density of the polymer film material. Process according to claim 14, characterized in that the gel grows more rapidly in the x-direction relative to the z-direction by increasing the width of the matrix space at a constant line removal rate of the device while maintaining a density of cellular film of the polymeric film material. 18. Process according to claim 14, characterized in that introducing a thermoplastic polymer material into the device comprises introducing an aromatic alguenyl polymer into the device. Process according to claim 14, characterized in that incorporating one or more blowing agents comprises incorporating one or more blowing agents into the thermoplastic polymer resin at a first pressure to form a gel, the first pressure is sufficient to prevent - Foaming of the gel, the one or more blowing agents comprise partially or completely hydrogenated HCFC's, HFC's, HC's, carbon dioxide, other inert gases and their mixtures. 33 20. Process according to claim 14, characterized in that introducing a thermoplastic polymer resin to the device comprises introducing a thermoplastic polymer resin into the device, the thermoplastic polymer resin having a weight average molecular weight of between about 30,000 and 500,000.